About this world
TOI-500 d is a Neptune-like planet orbiting TOI-500, an orange dwarf (type K6V) 155 light-years from Earth. It is about 0.57 times the size of Jupiter (its size estimated from its mass), with at least 0.1 Jupiter masses (a minimum, measured by radial velocity). It completes an orbit every 26.2 days at 0.16 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 471 K (198 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2022 by radial velocity with La Silla Observatory. The star wobbles toward and away from us, Doppler-shifting its spectrum. TOI-500 has 4 known planets; the others are TOI-500 b, TOI-500 c and TOI-500 e.